BLENHEIM, Ont. — Ontario Agriculture’s nutrient management specialist says progress toward phosphorus reduction targets in Lake Erie cannot be measured by testing the water.
Instead, the province’s farmers will need to work together on land to establish science-based models that demonstrate how improved practices provide a reduction benefit, Chris Brown said.
“As farmers, we need to know what’s happening on our land. We need that information so we get it right,” she told Seed Corn Growers of Ontario’s annual meeting March 7.
Water quality in Lake Erie, which is the shallowest of the Great Lakes, is already being monitored. Unfortunately, it takes time for reduced loading on land to be reflected in the lake, Brown said.
Read Also
Canada’s plant hardiness zones receive update
The latest update to Canada’s plant hardiness zones and plant hardiness maps was released this summer.
One reason is that the soil-attached phosphorus already in Lake Erie is slow to be released.
An agreement signed last summer between Ontario, Michigan and Ohio looks to reduce phosphorus loading in Lake Erie by 40 percent by 2025. An interim target of 20 percent was set for 2020.
The U.S. commitment is for a reduction of 3,316 tonnes, much of which is to be achieved within the Maumee River watershed that flows into Erie’s western basin. That leaves just 212 tons for Ontario, a far smaller amount but still a challenging target.
There are non-agricultural sources of phosphorus, but Brown said agriculture is a major contributor because it’s the dominant feature around the lake.
A good first step for farmers is to adopt the 4R approach: the right place, right time, right rate and right source for fertilizer. The voluntary, multi-stakeholder 4R Nutrient Stewardship Certification Program has already been launched in Ohio, Michigan and Indiana.
“There are now close to 4,000 farm operations certified in the States and it’s probably going to come here as well,” Brown said.
Ontario farmers, including the chair of the seed corn growers association, are already adopting practices that help reduce phosphorus losses.
Jeff Wilson said he now seeds a cover crop following peas and into standing seed corn.
“As soon you take your corn off, it really pops and you get quite a bit of biomass,” he said.
Cover crops and rotations that include wheat help improve soil structure and reduce phosphorus losses, Brown said. Wheat has also been proven to increase corn and soybean yields in the years after it was harvested.
Phosphorus reaches Lake Erie either tied to soil particles or in solution. Brown said the contribution of individual farmers to reduce loading is slight, but progress can be made by working together.
“If we work on a field scale, on a sub-watershed scale, we’re going to see some progress.”
Brown said farmers can also reduce nutrient losses by eliminating fall nutrient applications, especially winter-applied manure on frozen ground. Research shows 80 percent occurs from November to April.
Other steps include the establishment of riparian buffer strips and other measures that reduce wind and water erosion.
As an alternative to fence rows, Brown suggested farmers consider grassed tramways for sprayer traffic and permanent buffer strips seeded to a biomass crop such as switch grass that might be harvested as an energy crop.
Phosphorus loading in the Great Lakes was addressed in the wake of the increased incidence of algae blooms in the 1970s. These created oxygen-deprived zones in the lake and emitted toxins that affected the quality of drinking water.
The incidence of blooms in-creased in the 1990s, even though the amount of phosphorus entering the lake had already been reduced. There is partly blamed on the increasing number of storms linked to climate change.
“If we could stop all the soil erosion, we could get to our objective, but that’s hard to do when you get these intensive storms,” Brown said.
Ontario farmers within the Lake Erie watershed and along Lake Huron’s eastern shore have access to the Great Lakes Agricultural Stewardship Initiative.
“I think this program is a carrot, and we all like carrots better than sticks,” said Margaret May, field representative with the Ontario Soil & Crop Improvement Association.
“If you bite enough of the carrots, you won’t see the stick.”
The federal-provincial program pays up to $50,000 and will cover up to 60 percent of project costs in some instances.
Even farmers who have already implemented best practices can access funding, May said.
